Lecture 21

Question 1

Respiratory system

Answer 1

Starts at nostrils ends at alveoli. Supplies O2 and removes CO2 into blood. Reliant of respiratory muscles incl. diaphragm and thorax muscles and pleural coverings for respiration. Patency vital for efficient gas exchange and also involved in vocalisation.

Question 2

Upper respiratory system

Answer 2

Nasal cavities, nasopharynx, oropharynx, laryngopharynx, larynx

Question 3

Lower respiratory system

Answer 3

Trachea, carina, bronchi, bronchial tree, alveoli, lungs.

Question 3

Hyoid bones

Answer 3

The hyoid bone is a small, U-shaped bone located above the larynx and beneath the mandible, uniquely not articulating with any other bone. It connects the oral cavity, pharynx, and larynx, and serves as a mobile anchor for muscles and soft tissues, supporting tongue movement, swallowing, and speech.

Question 4

Larynx

Answer 4

Suspended from hyoid bone and attached to trachea below by soft membranes and ligaments therefore, highly mobile. Protects vocal folds through 4 separate cartilage connected via flexible ligaments and membranes. Guarding airways and has coughing reflex. Conducts air from laryngopharynx to trachea.

Question 5

Epiglottis

Answer 5

Folds down to close larynx so food wont enter larynx. Leaf-shaped. Posterior to tongue and hyoid bones. Anterior to a.c

Question 6

Thyroid cartilage

Answer 6

Shield shaped, encloses and anchors vocal folds. Anteriorlateral a.c, superior to c.cm inferior to hyoid, projects anteriorly.

Question 7

Cricoid cartilage

Answer 7

Ring. Inferior to t.c and a.c, superior to trachea.

Question 8

Arytenoid C

Answer 8

Bumps under mucosa, sits ontop of cricoid, pyramid shaped paired. Medial to t.c, superor to c.c. Slide and rotate to move vocal folds towards/away midline altering space between them (rima glottides)

Question 9

Internal features of larynx

Answer 9

Internal cavity of larynx narrows as lateral walls undulate forming 2 bilateral pairs of folds running between a.c and t.c. One is vestibular folds (false vocal folds) which is superior to vocal folds (true vocal cords). Space between folds is laryngeal ventricle. Space between vocal folds is rima glottidis where change in rima glottidis = change in sound.

Question 10

Trachea

Answer 10

Fibromuscular tube with cartilaginous rings around it. Extends inferior to larynx and provides air from laryngopharynx to lungs. Suspends from c.c and travels along vertebral bodies. Bifurcates into R and L primary (1º) bronchi at carina (at sternal angle). Stretch/recoil during respiration due to fibroelastic tissue between cartilage rings (16-20) opened posteriorly and finished off by trachealis muscle allowing trachea to sit against oesophagus allowing food to pass through

Question 11

Bronchi

Answer 11

R and L cartilage reinforced by primary bronchi pass behind the heart and into each lung root before branching. R is shorter than L, wider and more vertical (foreign substance likely to enter RL).

Question 12

Bronchi divisions

Answer 12

Repeated bronchi branching = bronchial tree. Primary bronchi/2ndary bronchi (3 on RHS, 2 on LHS)/tertiary bronchi/terminal bronchioles (cartilage free)/respiratory bronchioles/alveoli

Question 13

Bronchial trees

Answer 13

trachea -> 1º -> 2º -> terminal bronchioles -> respiratory bronchioles -> alveoli and alveoli sacs

Question 14

Lungs in pulmonary cavity

Answer 14

Lungs covered by pleura and occupy the two lateral pulmonary cavities of the thorax which lie on either side of mediastinum (and heart). Apex of lungs extends into root of neck above 1st rib while base rests on diaphragm in fibrous pericardium. Costal surfaces of lungs are against ribs, mediastinal surface is against heart.

Question 15

Right lung

Answer 15

Larger and wider than L but shorter as liver pushes up. Superior, middle and inferior lobe. Horizontal and oblique fissures where horizontal is in RL ONLY but oblique in both.

Question 16

Left lung

Answer 16

Smaller, longer and more narrow than RL. Superior and inferior lobe with oblique fissure only. Cardiac notch forms abdnormal shape in S.L and lingula. Anterior aspect of lung wraps around heart while posterior is wide and blunt.

Question 17

Pulmonary hilum

Answer 17

Structures enters and leaves lungs medially via pulmonary hilum which is surrounded by pleural sleeve that inferiorly drapes to create pulmonary ligament.

Question 18

R hilum

Answer 18

Bronchus: Typically located posterior.

Pulmonary artery: Lies anterior to the bronchus and slightly superior.

Pulmonary veins: Positioned anterior and inferior to both the bronchus and artery.

BAV (superior to inferior)

Question 19

L hilum

Answer 19

Pulmonary artery: Lies superior to the bronchus.

Bronchus: Located posterior and inferior to the artery.

Pulmonary veins: Also anterior and inferior, like on the right.

ABV (superior to inferior)

Question 20

Visceral relations

Answer 20

Twist in LPA and left bronchus = LPA being superior (not anterior) to bronchus in LL

Question 21

Pleural layers

Answer 21

Fluid-filled. During development, lungs grow into a pleura sac wrapped in 2 serous pleural layers

Question 22

Visceral pleura

Answer 22

Adheres to lungs and extends into fissures

Question 23

Parietal pleura

Answer 23

Adheres to thoracic wall, extends into root of neck and does not extend into lung fissures.

Question 24

Pleura relation to hilum

Answer 24

Visceral and parietal pleura are continuous at lung hilum and drapes inferiorly to form pulmonary ligament. Between layers, there's serous fluid to keep pleural layers together by fluid surface tension. Maintenance of surface tension prevents lung recoil due to it's elasticity. If blood/air enters pleural fluid, surface tension is broken and lung recoil cannot be resisted and lung collapses.

Question 25

Intercostal nerve

Answer 25

In neurovascular bundles. Sensory innervation of costal parietal pleura which overlies ribs. Motor innervation of the intercostal muscles.

Question 26

Phrenic nerve

Answer 26

Sensory innervation of diaphragmatic parietal pleura. Motor innervation of the diaphragm.

Question 27

Vagus nerve

Answer 27

Sensory innervation of visceral pleura. Parasympathetic motor innervations (constricts bronchi, dilates pulmonary vessels, increase secretions, decrease respiratory rate)

Question 28

Sympathetic trunk

Answer 28

Sensory innervation of visceral pleura, sympathetic autonomic innervation (opposite of vagus nerve).